1. Technical Field
The present disclosure relates to a display device, and more particularly, to a liquid crystal display (LCD).
2. Discussion of the Related Art
A liquid crystal display (LCD) is one of the most widely used flat panel displays. An LCD includes two panels provided with field-generating electrodes such as pixel electrodes and a common electrode and a liquid crystal (LC) layer interposed therebetween. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer, which determines orientations of LC molecules in the LC layer to adjust polarization of incident light.
Among the LCDs, a vertical alignment (VA) mode LCD, which aligns LC molecules such that the long axes of the LC molecules are perpendicular to the panels in the absence of an electric field, exhibits a high contrast ratio and wide reference viewing angle. The reference viewing angle is defined as a viewing angle resulting in a contrast ratio equal to 1:10 or as a limit angle for the inversion in luminance between the grays.
The wide viewing angle of the VA mode LCD can be realized through the use of cutouts in the field-generating electrodes and/or protrusions on the field-generating electrodes. Since the cutouts and the protrusions influence the tilt directions of the LC molecules, the tilt directions can be distributed into several directions by using the cutouts and the protrusions such that the reference viewing angle is widened.
However, the VA mode LCD has relatively poor lateral visibility compared with front visibility. For example, a patterned VA (PVA) mode LCD having the cutouts can result in an image that becomes bright as a viewer moves away from the front vantage point, and in the worse case, the luminance difference between high grays vanishes such that the images cannot be perceived.
In addition, in LCDs, a pixel region is divided into a plurality of domains by cutouts or protrusions formed in or on a pixel electrode and a common electrode. However, the domains are likely to have different areas, and thus, it is difficult to provide uniform vertical and horizontal visibility.